Adjustable gap for a fluid dynamic bearing

ABSTRACT

A fluid bearing motor. The fluid bearing motor includes a stationary sleeve, a backiron, a hub coupled to the backiron, and a gap forming component. The hub is operable to rotate with respect to the stationary sleeve. The gap forming component is attached to the stationary sleeve and forms a gap between the stationary sleeve and the backiron. The size of the gap dynamically changes in response to changes in temperature.

TECHNICAL FIELD

Embodiments of the present invention relate to fluid dynamic bearings.More specifically, embodiments of the present invention relate to a gapformation for providing resistance to oil evaporation.

BACKGROUND

Disc drive memories are used in many electronic devices, e.g., personalcomputers (PC), portable computers, digital cameras, digital videocameras, video game consoles, personal music players, etc. Disc drivememories store digital information recorded on concentric tracks of amagnetic disc medium.

Usually one disc is rotatably mounted on a spindle and the informationstored within the disc is accessed using read/write heads ortransducers. The read/write heads are located on a pivoting arm thatmoves radially over the surface of the disc. The discs are rotated athigh speeds during operation using an electric motor located inside ahub or below the discs. Magnets on the hub interact with a stator tocause rotation of the hub relative to the stator.

One conventional disc drive utilizes a spindle motor with a fluiddynamic bearing (FDB) to support the hub and discs for rotation. Thebearing reduces wear and tear along by reducing friction whilemaintaining the alignment between the spindle and the shaft.

SUMMARY

A fluid bearing motor. The fluid bearing motor includes a stationarysleeve, a backiron, a hub coupled to the backiron, and a gap formingcomponent. The hub is operable to rotate with respect to the stationarysleeve. The gap forming component is attached to the stationary sleeveand forms a gap between the stationary sleeve and the backiron. The sizeof the gap dynamically changes in response to changes in temperature.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention are illustrated by way of example,and not by way of limitation, in the figures of the accompanyingdrawings and in which like reference numerals refer to similar elementsand in which:

FIG. 1 shows a top view of a disc drive data storage system inaccordance with one embodiment of the present invention.

FIG. 2 shows a sectional side view of a fluid dynamic bearing spindlemotor in accordance with one embodiment of the present invention.

FIG. 3 shows one sectional side view of a fluid dynamic bearing motor inaccordance with one embodiment of the present invention.

FIG. 4 shows a portion of a sectional side view of a fluid dynamicbearing motor under pressure in accordance with one embodiment of thepresent invention.

FIG. 5 shows a portion of a sectional side view of a fluid dynamicbearing motor under pressure using an adjustable gap setting device inaccordance with one embodiment of the present invention.

FIG. 6 shows a second sectional side view of a fluid dynamic bearingmotor in accordance with one embodiment of the present invention.

DETAILED DESCRIPTION

A fluid bearing motor. The fluid bearing motor includes a stationarysleeve, a backiron, a hub coupled to the backiron, and a gap formingcomponent. The hub is operable to rotate with respect to the stationarysleeve. The gap forming component is attached to the stationary sleeveand forms a gap between the stationary sleeve and the backiron. The sizeof the gap dynamically changes in response to changes in temperature.

According to one embodiment, a fluid bearing motor may include astationary sleeve, a backiron, a hub coupled to the backiron, and a gapforming component. The hub is operable to rotate with respect to thestationary sleeve. The gap forming component may be attached to thestationary sleeve and forms a gap between the stationary sleeve and thebackiron.

The gap size changes in response to changes in temperature. It isappreciated that the hub lifts up axially when the hub rotates, therebyincreasing the size of the gap. The axial lift decreases in response toan increase in temperature. The size of the gap is reduced in responseto an increase in temperature. The fluid bearing motor may include afluid circulation path formed between the backiron and the stationarysleeve and removes air from a journal bearing formed by the stationarysleeve. In one embodiment, the gap may be less than 50 micrometers.

The fluid bearing motor may further include a seal operable to contain afluid within the fluid circulation path. It is appreciated that the gapmay be formed axially.

In one embodiment, a fluid bearing motor may include a first component,a second component, and an adjustable gap component. The secondcomponent is operable to rotate with respect to the first component.According to one embodiment, the adjustable gap component is coupled tothe first component. The adjustable gap component forms a gap with thesecond component. It is appreciated that the gap changes in sizeresponsive to changes in temperature.

According to one embodiment the gap size decreases responsive to anincrease in temperature. In one embodiment, the gap may be less than 50micrometers. The second component lifts up axially responsive to athrust bearing during rotation. The amount of axial lift changesresponsive to changes in temperature, e.g., the amount of the liftdecreases responsive to an increase in temperature.

In one particular embodiment, a motor includes a stationary sleeve, ashaft, a hub, a backiron, and an adjustable gap forming component. Theshaft is operable to rotate with respect to the stationary sleeve. Thehub is operable to rotate with respect to the stationary sleeve inresponse to the shaft rotating. According to one embodiment, thebackiron is affixed to the hub and further affixed to the shaft. Theadjustable gap forming component is attached to the stationary sleeveand forms a gap between the stationary sleeve and the backiron. The gapsize changes in response to the hub rotation. Moreover, the gap sizechanges responsive to changes in temperature.

According to one embodiment, the hub lifts up axially when the hubrotates. Thus, the axial lift of the hub increases the gap size. Theaxial lift of the hub decreases responsive to an increase intemperature.

According to one embodiment, the gap size decreases in response to anincrease in temperature. In one exemplary embodiment, the gap size isless than 50 micrometers.

Accordingly, the established gap according to the embodiments may bereduced. Furthermore, the gap is adjusted as temperature changes,thereby compensating for any increase in oil evaporation rate withincreased temperature. Moreover, the gap adjusts as the hub lifts off.As a result, the gap according to the embodiments of the presentinvention may further reduce oil evaporation rate.

Reference will now be made in detail to embodiments, examples of whichare illustrated in the accompanying drawings. While the embodiments willbe described in conjunction with the drawings, it will be understoodthat they are not intended to limit the embodiments. On the contrary,the embodiments are intended to cover alternatives, modifications andequivalents. Furthermore, in the following detailed description,numerous specific details are set forth in order to provide a thoroughunderstanding. However, it will be recognized by one of ordinary skillin the art that the embodiments may be practiced without these specificdetails. In other instances, well-known methods, procedures, components,and circuits have not been described in detail as not to unnecessarilyobscure aspects of the embodiments.

Generally, the terms “axially” or “axial direction” refers to adirection along a centerline axis length of a shaft, e.g., along axis260 of shaft 202, and “radially” or “radial direction” refers to adirection perpendicular to the centerline axis 260, and passing throughcenterline axis 260. The terms “upper”, “lower”, “top”, “bottom”,“height” and the like, are applied in a sense related to normal viewingof the figures rather than in any sense of orientation during particularoperation. These orientation labels are provided to facilitate and aidunderstanding of the figures as described in this description and shouldnot be construed as limiting the scope of the embodiments.

Oil evaporation and oil leakage may lead to excessive bearing wear influid dynamic bearing motors. Oil evaporation may be controlled using asmall gap, e.g., labyrinth, separating the oil from outside components.According to one embodiment, the gap may reduce the amount of oil thatescapes an oil channel or an oil reservoir. The effectiveness of the gapmay vary depending on various factors, e.g., gap positioning, gaplength, and gap area. In one embodiment, the gap may be dynamicallyreduced.

Embodiments enable the gap to be adjusted to a desired and accuratearea. In one embodiment, the gap controls fluid evaporation of a fluiddynamic bearing motor. In one embodiment the gap size adjusts astemperature changes. For example, the size of the gap may automaticallybe reduced at higher temperatures to prevent oil evaporation that occursat higher temperatures. It is appreciated that the gap, e.g., labyrinth,according to one embodiment reduces oil evaporation that occurs morereadily for low viscosity oils. Furthermore, the adjustable gap mayincrease the performance of low profile motors with limited areaavailable for axial gap.

It is appreciated that the adjustable gap for reducing oil evaporationin accordance with embodiments may be used in various devices, e.g.,disc drive memory systems, low profile disc drive memory systems,spindle motors, brushless DC motors, ball bearing assemblies, fluiddynamic bearings, hydrodynamic bearings, hydrostatic bearings,stationary and rotatable components such as motors with conicalbearings, etc. It is further appreciated that the gap according toembodiments may be employed with a fixed shaft or a rotating shaft.

Referring to FIG. 1, a top view of a disc drive data storage system 110in accordance with one embodiment of the present invention is shown. Thedisc drive 110 includes a housing base 112 that forms a sealedenvironment with a cover 114. The sealed environment protects theinternal components from contamination by elements outside of the sealedenvironment. The disc drive 110 further includes a disc pack 116, whichis mounted for rotation on a spindle motor (described in FIG. 2) by adisc clamp 118.

The disc pack 116 includes a plurality of individual discs mounted forco-rotation about a central axis. Each disc surface may be associatedwith heads 120 (read head and write head) operable to communicate withthe disc surface. In one exemplary embodiment, heads 120 are supportedby flexures 122. The flexures are attached to head mounting arms 124 ofactuator body 126.

According to one embodiment, an actuator may be a rotary moving coilactuator that includes a voice coil motor 128. The voice coil motor 128rotates the actuator body 126 with its attached heads 120 about a pivotshaft 130. Accordingly, the heads 120 may be positioned over a desireddata track along an arc path 132. As such, heads 120 may read and writemagnetically encoded information on the surfaces of the disc pack 116 atselected locations.

A flex assembly may provide electrical connection paths for the actuatorassembly while allowing pivotal movement of the actuator body 126. Theflex assembly (not shown) terminates at a flex bracket for communicationto a printed circuit board mounted to the bottom of the disc drive 110connected to head wires. The head wires are routed along the actuatorarms 124 and the flexures 122 to the heads 120. The printed circuitboard may include a circuitry for controlling the write currents appliedto the heads 120 during a write operation and a preamplifier foramplifying read signals generated by the heads 120 during a readoperation.

Referring now to FIG. 2, a sectional side view of a fluid dynamicbearing spindle motor in accordance with one embodiment is shown. Thespindle motor includes a stationary component and a rotatable component.The rotatable component rotates relative to the stationary component anddefines a fluid dynamic journal bearing 206 and a thrust bearing 207there between.

In this exemplary embodiment, the rotatable components include a shaft202 and a hub 210. The hub 210 includes a disc carrier member thatsupports the rotation of the disc pack 116 about the shaft 202. Theshaft 202 and the hub 210 are affixed to a backiron 215 and a magnet216. One or more magnets 216 are attached to a periphery of backiron215.

The magnets 216 interact with a stator winding 214 attached to a base220 to cause the hub 210 to rotate. The magnets 216 may be formed as aunitary annular ring or may be formed as a plurality of individualmagnets that are spaced about the periphery of hub 210. The magnets 216are magnetized to form two or more magnetic poles. The stationarycomponents include a sleeve 204 and the stator winding 214 affixed tothe base 220. The fluid dynamic journal bearing 206 is establishedbetween the sleeve 204 and the shaft 202.

According to one embodiment, fluid, e.g., lubricating oil or aferromagnetic fluid, fills interfacial regions between shaft 202 andsleeve 204 as well as between other stationary and rotatable components.It is appreciated that the lubricating fluid described herein isexemplary and not intended to limit the scope of the embodiments of thepresent invention. For example, the fluid may include a lubricatingliquid or a combination of a lubricating liquid and lubricating gas.

In one embodiment, the shaft 202 and the sleeve 204 include pressuregenerating grooves. It is appreciated that the pressure generatinggrooves may include asymmetric grooves and/or symmetric grooves.Asymmetric grooves and symmetric grooves may have a pattern includingone of a herringbone pattern and a sinusoidal pattern. The herringbonepattern and the sinusoidal pattern are operable to induce fluid flow inthe interfacial region in order to generate a localized region ofdynamic high pressure and radial stiffness.

It is appreciated that pressure is built up in each of its groovedregions when the shaft 202 rotates. According to one embodiment, theshaft 202 supports the hub 210 for constant rotation.

In one exemplary embodiment, a fluid circulation path 209 is formedthrough the sleeve 204 to circulate the fluid through the journalbearing 206. The fluid circulation path 209 may purge air from thejournal bearing 206 via the reservoir 212 contained by fluid meniscus222.

Referring now to FIG. 3, one sectional side view of a fluid dynamicbearing motor in accordance with one embodiment of the present inventionis shown. In this embodiment, the fluid dynamic bearing motor includes alabyrinth component 228 adjoining the sleeve 204. A gap 208, e.g.,labyrinth, is formed between the labyrinth component 228 and thebackiron 215. The gap 208 formed by the labyrinth component 228dynamically adjusts in size, thereby reducing oil evaporation as thetemperature increases. It is appreciated that the fluid meniscus 222 maycontain the bearing fluid sealed therein. It is appreciated that in oneexemplary embodiment the gap 208 may be situated beyond the fluiddynamic bearing fluid and the meniscus 222 sealing the fluid dynamicbearing fluid.

The gap 208 may be accurately adjusted to a desired area, as describedin FIGS. 4 and 5 below. The length of the gap 208 may vary from 0micrometers to 15 micrometers (a micro-labyrinth gap in one example).According to one embodiment, the length is measured from the labyrinthcomponent 228 to the stationary component. In one exemplary embodiment,the length is measured from the labyrinth component 228 to the rotatablecomponent, e.g., backiron 215, when the rotatable component isstationary with respect to the stationary component.

It is appreciated that larger gaps, e.g., labyrinths, may beestablished. For example, a labyrinth gap of greater than 15 micrometers(um) may be established when the rotatable component, e.g., backiron215, is stationary with respect to the stationary component. It isappreciated that a gap smaller than 50 um is achievable.

According to one embodiment, the hub 210 lifts up axially relative tothe sleeve 204 as the motor spins. The axial lift of the hub 210 is duein part to a force created by the thrust bearing 207. The distance oflift off is described as fly height.

In an embodiment, the gap 208 increases in area due to the occurrence offly height when the hub 210 rotates with respect to the sleeve 204. Itis appreciated that the fly height occurs after the gap 208 is adjustedand established. In one exemplary embodiment, the gap 208 between thefacing surfaces of the labyrinth component 228 and the backiron 215 isset to 20 micrometers or less when the hub 210 is rotating relative tothe sleeve 204. It is appreciated that a gap of 20 micrometers may beestablished provided that the fly height is 5 micrometers and apreviously set labyrinth gap is 15 micrometers or less.

It is appreciated that gap 208 extending radially is exemplary and notintended to limit the scope of the present invention. For example, thegap may extend axially.

The area of the gap 208 may change and adjust automatically anddynamically as the temperature of the fluid dynamic bearing changes. Inone exemplary embodiment, the labyrinth component 228, a stationarycomponent, e.g., sleeve 204, or a rotatable component, e.g., hub 210,move in response to changes in temperature, thereby dynamically changingthe area of the gap 208. For example, the gap 208 adjoining the journalbearing 206 may extend substantially in the same direction as the thrustbearing 207. It is appreciated that the terms area of the gap 208 andsize of the gap 208 are used interchangeably throughout the detaileddescription.

In one exemplary embodiment, the fly height changes as motor temperaturechanges. For example, the fly height of the hub 210 is lower when thetemperature is higher and vice versa. The fly height is also related tochanges in oil viscosity as temperature changes.

In one embodiment, the gap automatically adjusts along with hub 210 liftoff, as temperature changes. For example, the gap is reduced at hightemperatures when fluid evaporation is greater. As a result, the changein the gap size compensates for the increased fluid evaporation rate.Therefore, gap 208 reduces fluid evaporation from the fluid dynamicbearing motor. Reducing fluid evaporation is particularly useful for lowviscosity oils. Furthermore, reducing fluid evaporation is useful in lowprofile motors due to limited availability of axial gaps.

Referring now to FIG. 4, a portion of a sectional side view of a fluiddynamic bearing motor under pressure in accordance with one embodimentof the present invention is shown. The fluid dynamic bearing motorincludes a rotatable shaft 402 and a hub 410. The hub 410 rotates withrespect to a stationary sleeve 404 forming a fluid dynamic bearing 406and a thrust bearing 407. A fluid seal 422 contains the bearing fluid.

It is appreciated that specific physical dimensions may vary withincertain practical limits without significantly affecting thefunctionality of a motor. Tolerances may be specified to allowreasonable leeway for imperfections and inherent variability withoutcompromising performance. The present invention can reduce or eliminatedesign concerns for component tolerance when establishing a gap, e.g.,gap 408. For example, embodiments of the present invention allow asmaller gap that may be automatically adjusted to a desired and accuratearea.

In one embodiment, a labyrinth component 428 is forced toward a backiron415 until the two components become in contact. It is appreciated thatin one exemplary embodiment, the labyrinth component 428 may be forcedtoward some other component, e.g., a stationary component or a rotatablecomponent, in order to make contact with the backiron 415. Any means maybe used to apply the force. For example, hand pressing may exert thedesired force.

In one embodiment, the gap is established when the rotatable component,e.g., hub 410, is stationary with respect to the stationary component,e.g., the sleeve 404. The area of the gap 408 is not limited bycomponent tolerances of the labyrinth component 428, the backiron 415,or any rotatable or stationary components. In one embodiment, acomponent spring back by the labyrinth component 428 or the facingcomponent may occur.

According to one embodiment, the hub 410 dynamically lifts up axiallywith respect to the sleeve 404 as the motor spins. The axial lift of thehub 410 is due in part to forces created by the thrust bearing 407. Inan embodiment, the gap 408 increases in area due to the fly height thatoccurs when hub 410 rotates with respect to the sleeve 404. It isappreciated that the fly height occurs after the gap 408 is adjusted andestablished. In one exemplary embodiment, a gap 408 size of about 5micrometers can be established when the hub 410 rotates relative to thesleeve 404. It is appreciated that a gap size of 5 micrometers may beestablished provided that a fly height is 5 micrometers and a previouslyset gap is 0 micrometers. It is appreciated that the gap may be slightlylarger depending on the occurrence of spring back of a facing component.The gap 408 may be adjusted to greater than 5 micrometers, as describedbelow with reference to FIG. 5. In one embodiment, the gap 408 isestablished by placing the labyrinth component 428 in contact with astationary component and/or a rotatable component.

Accordingly, the gap automatically adjusts as the hub lifts off and asthe temperature changes. Thus, the gap is reduced at high temperatureswhen fluid evaporation is greater. As a result, the dynamic change inthe gap size for reducing fluid evaporation rate from the fluid dynamicbearing motor. Reducing fluid evaporation is particularly useful for lowviscosity oils. Furthermore, reducing fluid evaporation is useful in lowprofile motors due to limited availability of axial gaps.

Referring now to FIG. 5, a portion of a sectional side view of a fluiddynamic bearing motor under pressure using an adjustable gap settingdevice in accordance with one embodiment of the present invention isshown. The fluid dynamic bearing motor includes a rotatable shaft 502and a hub 510. The hub 510 rotates with respect to a stationary sleeve504 forming a fluid dynamic bearing 506 and a thrust bearing 507. Afluid seal 522 contains the bearing fluid.

It is appreciated that the embodiments of the present invention mayreduce design concerns for component tolerance when establishing alabyrinth gap 508 because the gap 508 is adjustable to a desired andaccurate area. In one embodiment, labyrinth component 528 is forcedtoward a backiron 515 using a gap setting device 550.

The gap setting device 550 is used to establish the labyrinth gap 508between the labyrinth component 528 and the backiron 515. It isappreciated that the gap setting device 550 may also be used toestablish the labyrinth gap 508 between the labyrinth component 528 anda stationary component, e.g., the sleeve 504, or a rotatable component,e.g., the hub 510. In this exemplary embodiment, the gap setting device550 includes a “lip” or protrusion extending beyond the labyrinthcomponent 528 and toward the backiron 515. The lip portion is operableto establish the labyrinth gap 508. It is appreciated that the lipportion is exemplary and not intended to limit the scope of theembodiments of the present invention. For example, a plate without a lipmay used.

In one embodiment, the gap setting device 550 applies pressure to thelabyrinth component 528 toward the backiron 515. The application of thisforce ultimately causes the gap setting device 550 to contact thebackiron 515. Thus, the gap 508 is formed between the labyrinthcomponent 528 and the backiron 515. After the labyrinth gap 508 is set,the gap setting device 550 may be removed.

According to one embodiment, the gap setting device 550 applies pressureto the labyrinth component 528 toward a stationary component or arotatable component until the gap setting device 550 becomes in contactwith the stationary or the rotatable component. In an embodiment, thelabyrinth gap 508 is established when the rotatable component, e.g., thehub 510, is stationary with respect to the stationary component, e.g.,the sleeve 504.

Any means may be used to apply the force. For example, hand pressure mayexert the desired force to the gap setting device 550. Applying force tothe gap setting device 550 transfers the applied force to the labyrinthcomponent 528. Accordingly, the area of the labyrinth gap 508 is notlimited by component tolerances of the labyrinth component 528, thebackiron 515, or rotatable or stationary components. In one embodiment,a component spring back by the labyrinth component 528 against the gapsetting device 550 may occur.

The labyrinth gap 508 is equal to the distance from the labyrinthcomponent 528 to the backiron 515 (or to a stationary or rotatablecomponent) when the rotatable component is stationary with respect tothe stationary component. In one embodiment, the labyrinth gap 508 isequal to the distance that the gap setting device 550 extends betweenfacing surfaces of the labyrinth component 528 and the backiron 515.

A labyrinth gap of less than 20 micrometers may be established betweenthe facing surfaces of the labyrinth component 528 and the backiron 515when the rotatable component e.g., the hub 510, rotates relative to thestationary component, e.g., the sleeve 504, and when the facingcomponents lift apart. It is appreciated that a labyrinth gap of lessthan 20 micrometers may be established between the facing surfaces ofthe labyrinth component 528 and a stationary component, e.g., the sleeve504, or a rotatable component, e.g., the hub 510. It is appreciated thatsetting a labyrinth gap size of less than 20 micrometers is exemplaryand not intended to limit the scope of the present invention. Forexample, the labyrinth gap may be set to greater than 20 micrometersusing the gap setting device 550.

The labyrinth gap 508 is established by situating the gap setting device550 to establish the labyrinth gap 508 between the labyrinth component528 and a stationary component, e.g., the sleeve 504, or a rotatablecomponent, e.g., the hub 510. In an embodiment, the labyrinth gap 508 issmaller in area than can be provided if component tolerance were adesign consideration.

Accordingly, the gap automatically adjusts along as the hub lifts offand as the temperature changes. Thus, the gap size is reduced at hightemperatures when fluid evaporation is greater. As a result, the changein the gap size reduces the overall fluid evaporation rate of the fluiddynamic bearing motor. Reducing fluid evaporation may be useful for lowviscosity oils. Furthermore, reducing fluid evaporation may be useful inlow profile motors due to limited availability of axial gaps.

Referring now to FIG. 6, a second sectional side view of a fluid dynamicbearing motor in accordance with one embodiment of the present inventionis shown. The fluid dynamic bearing motor includes a rotatable shaft 602and a hub 610. The hub 610 rotates with respect to a stationary sleeve604 forming a fluid dynamic bearing 606 and a thrust bearing 607. Afluid seal 622 contains the bearing fluid therein.

A labyrinth gap 608 is dynamically adjusted to a desired and accuratearea (as described with respect to FIGS. 4 and 5). In this embodiment,the rotatable component, e.g., the hub 610, is stationary with respectto the stationary component, e.g., the sleeve 604. Accordingly, alabyrinth component 628 becomes in contact with a backiron 615.

According to one embodiment, the hub 610 dynamically lifts up axiallywith respect to the sleeve 604 as the motor spins. The axial lift of thehub 610 is due in part to forces created by the thrust bearing 607. Inone embodiment, the labyrinth gap 608 increases in area when the hub 610rotates with respect to the sleeve 604 subsequent to establishment ofthe labyrinth gap 608.

It is appreciated that the labyrinth gap 608 size between the facingsurfaces of the labyrinth component 628 and the backiron 615 may becomeless than 20 micrometers when the hub 610 rotates relative to the sleeve604. It is appreciated that the labyrinth gap 608 extending radially isexemplary and is not intended to limit the scope of the embodiments ofthe present invention. For example, the labyrinth gap 608 may extendaxially. It is further appreciated that the labyrinth gap 608 beingsituated below a fluid seal 622 is exemplary and not intended to limitthe scope of the embodiments of the present invention.

Accordingly, the gap is dynamically adjusted as temperature changes,thereby compensating for any increase in oil evaporation rate astemperature increases. Moreover, the gap adjusts as the hub lifts off.As a result, the gap further reduces the oil evaporation rate.

Embodiments described herein may reduce oil evaporation while reducingpower consumption with respect to a fluid bearing of a motor. Moreparticularly, embodiments may reduce oil evaporation as temperatureincreases.

The foregoing description, for purpose of explanation, has beendescribed with reference to specific embodiments. However, theillustrative discussions above are not intended to be exhaustive or tolimit the invention to the precise forms disclosed. Many modificationsand variations are possible in view of the above teachings.

1. A fluid bearing motor comprising: a stationary sleeve; a backiron; ahub coupled to said backiron, wherein said hub is operable to rotatewith respect to said stationary sleeve; and a gap forming componentattached to said stationary sleeve and forming a gap between saidstationary sleeve and said backiron, wherein a size of said gap changesin response to changes in temperature.
 2. The fluid bearing motor asdescribed in claim 1, wherein said hub dynamically lifts up axiallyresponsive to hub rotation, and wherein said size of said gapdynamically increases in response to axial lift of said hub.
 3. Thefluid bearing motor as described in claim 3, wherein said axial liftdecreases in response to an increase in temperature.
 4. The fluidbearing motor as described in claim 1, wherein said size of said gap isreduced in response to an increase in temperature.
 5. The fluid bearingmotor as described in claim 1 further comprising a fluid circulationpath formed between said backiron and said stationary sleeve.
 6. Thefluid bearing motor as described in claim 5, wherein said fluidcirculation path is operable to remove air from a journal bearing formedby said stationary sleeve.
 7. The fluid bearing motor as described inclaim 5 further comprising a seal operable to contain a fluid withinsaid fluid circulation path.
 8. The fluid bearing motor as described inclaim 1, wherein said gap is formed axially.
 9. The fluid bearing motoras described in claim 1, wherein said size of said gap is less than 50micrometers.
 10. A fluid bearing motor comprising: a first component; asecond component operable to rotate with respect to said firstcomponent; and an adjustable gap component coupled to said firstcomponent, wherein said adjustable gap component forms a gap with saidsecond component, and wherein said gap changes in size responsive totemperature change.
 11. The fluid bearing motor as described in claim10, wherein said gap decreases in size responsive to temperatureincrease.
 12. The fluid bearing motor as described in claim 10, whereinsaid gap is less than 50 micrometers.
 13. The fluid bearing motor asdescribed in claim 10, wherein said second component lifts up axiallyresponsive to a thrust bearing during rotation.
 14. The fluid bearingmotor as described in claim 13, wherein an amount of lift of said secondcomponent changes responsive to temperature change.
 15. The fluidbearing motor as described in claim 14, wherein said amount of said liftdecreases responsive to temperature increase.
 16. A motor comprising: astationary sleeve; a shaft operable to rotate with respect to saidstationary sleeve; a hub operable to rotate with respect to saidstationary sleeve in response to said shaft rotating; a backiron affixedto said hub and further affixed to said shaft; and an adjustable gapforming component attached to said stationary sleeve, wherein saidadjustable gap forming component forms a gap between said stationarysleeve and said backiron, wherein a size of said gap changes in responseto said hub rotating and in response to temperature change.
 17. Themotor as described in claim 16, wherein said hub lifts up axially whensaid hub rotates, and wherein said size of said gap increases inresponse to axial lift of said hub.
 18. The motor as described in claim16, wherein said hub lifts up axially when said hub rotates, and whereinaxial lift of said hub decreases responsive to temperature increase. 19.The motor as described in claim 16, wherein said size of said gapdecreases in response to temperature increase.
 20. The motor asdescribed in claim 16, wherein said size of said gap is less than 50micrometers.